Shaft for a marking instrument



FIG. 1 is a top plan view of a shaft for a marking instrument showing my new design;

FIG. 2 is an enlarged scale left end elevational view;

FIG. 3 is an enlarged scale cross-sectional view thereof taken along line 3--3 of FIG. 1; and

FIG. 4 is a modified form of the shaft for a marking instrument.

The left end view of the modified embodiment at FIG. 4 is essentially the same as FIG. 2 but with the shading indicating the direction of the twist being reversed. 

The ornamental design for a shaft for a marking instrument, as shown and described. 